1. Field of the Invention
The present invention relates to an email transmission apparatus, an email transmission method, and an email transmission program. The present invention particularly relates to a method for reducing transmission of an email to a wrong address in an email transmission system such as a personal computer.
2. Description of the Related Art
With the proliferation of the Internet of recent years, the use of emails via providers (Internet access providers) is expanding rapidly, and emails have established themselves as communication means. Additionally, with the start of high-speed packet communication services for digital mobile phones, emails nowadays are transmitted/received also by use of mobile information terminals such as a notebook computer and a personal digital assistant (PDA). With the widespread use of emails, an email system is equipped as standard equipment on a main OS, a World Wide Web (WWW) browser and the like for a personal computer, and this makes it easy to make communications through emails.
FIG. 1 shows the configuration of a conventional typical email system. The email system includes mail client software 05 and a mail address database 06. The mail client software 05 has mail creating means 01, mail address storage control means 03 and the like.
The mail creating means 01 temporarily stores a mail message and a designated destination address in a memory, which are inputted by a sender (a user), and obtains a plurality of addresses similar to the inputted address from the mail address database 06 via the mail address storage means 03 by making a lexical analysis on a part of the designated address. Furthermore, the mail creating means 01 selectably displays the plurality of obtained addresses in a mail header, and allows a message being a main body to be edited and thereby the main body of a mail to be created. Moreover, the mail creating means 01 provides a user with means for transmitting the created email, and sends the email onto a network.
The mail address storage control means 03 has functions of storing and reading a mail address in and from the mail address database 06 (an address book). The mail address storage control means 03 obtains mail addresses from the mail address database 06, and passes the addresses to the mail creating means 01. In addition, the mail address storage control means 03 accepts a request to register a source address of a receive mail in the mail address database 06. A sender is provided with an opportunity to confirm the correctness of a displayed address that is one of the addresses extracted from the mail address database 06 as a result of the lexical analysis on a designated address, and thereby displayed as candidates.
In this manner, in the conventional email system, the mail address storage control means 03 notifies a sender of destination address candidates having lexical units similar to an address designated by the sender and extracted from the mail address database 06 (the address book), and the sender checks the destination address visually, in order to take measures to prevent the transmission of an email to a wrong address (hereinafter, “transmission to a wrong address” is referred to as “mis-transmission.”). When the sender designates a plurality of email addresses as destination addresses of a send mail, the sender needs to repeat a visual check on all the email addresses. Accordingly, it is not possible to eliminate a human error in a check.
When the occurrence of an error in a check on the wrong input of a destination address causes mis-transmission, the mistakenly transmitted mail discomforts the receiver of the mail, and causes useless communication traffic. The biggest problem of mis-transmission is that: there is a risk of leaking information to a third party; and a company to which the sender belongs suffers social damage. When a plurality of addresses are designated in the CC list of a receive mail and a return function is used for those addresses, even if a check alert on a return mail is notified, there may be a mistake in checking some addresses. In this case, mis-transmission to addresses that are not supposed to be transmitted to is caused.
There are two conventional techniques as a measure against the mis-transmission of an email. The first conventional technique is to notify a possibility of mis-transmission as an alert message by comparing a destination address inputted at the time of transmitting an email with a mail address previously registered in an address database (an address DB or an address book) (comparison with the address DB).
The second conventional technique is to alert a possibility of mis-transmission by performing a lexical analysis on an inputted destination address and then comparing each lexical unit of a designated address with a lexical unit corresponding to an address recorded in an address database (an address DB) (a lexical analysis+reference to the address DB).
The first conventional technique includes a technique, described in Japanese Patent Application Laid-open Publication No. 2001-337897, for judging “whether or not an inputted address is a non-transmittable address” and for notifying an alert. Japanese Patent Application Laid-open Publication No. 2001-337897 shows a mail transmission apparatus which registers the destination address of a non-transmittable mail in a database as a non-transmittable address at the time of receiving a return mail, and checks whether or not a destination address agrees with the non-transmittable address by referring to the database at the time of transmitting an email.
For example, Japanese Patent Application Laid-open Publication No. 2001-290715, No. 2002-324029, and No. 2001-230802, in which a lexical analysis is performed on a designated address and an address extracted from an address database is compared with the designated address at lexical level, are given as the second conventional measure against mis-transmission.
Japanese Patent Application Laid-open Publication No. 2001-290715 provides a sender with an opportunity of a check by, when inputting a part of a lexical unit of a mail address, retrieving similar addresses from a mail address database on the basis of the lexical unit, and displaying a plurality of addresses.
Japanese Patent Application Laid-open Publication No. 2002-324029 provides a method for preventing an email from being mis-transmitted by: dividing a destination address into domains (lexical units) and classifying the domains into hierarchical levels; comparing the destination address with a reference domain sequentially and hierarchically; and issuing an alert message on the basis of the comparison result on whether or not the agreed lexical unit exceeds the threshold value of a hierarchy level.
Japanese Patent Application Laid-open Publication No. 2001-230802 prevents mis-transmission by: determining whether or not a lexical unit is an assigned name to be transmitted frequently by a sender on the basis of the lexical unit meaning the assigned name of a mail address; and displaying a check message for an alert, taking it as possibly causing mis-transmission to a different destination which exists in a register (an address book) when the assigned name (the lexical unit) is different from the one of the sender registered in a mail address database.
The techniques described in Japanese Patent Application Laid-open Publication No. 2001-337897, No. 2001-290715, No. 2002-324029, and No. 2001-230802 are not useful measures to avoid mis-transmission even if a lexical analysis is performed, in a case where there exist wrong destination addresses in an address database. For example, FIG. 2 shows a case where mail client software refers to an address database (an address book) in order to select a candidate related to a lexical unit, John, which is a part of an inputted address. Since the lexical unit, John, of the correct mail address is common in the address database, when a sender designates the lexical unit in a mail header in the mail creating means, a plurality of similar addresses, for example, two of John-A and John-B, are displayed as candidates. When a plurality of addresses including the commonly lexical unit of John exist, the mis-transmission occurs by the sender mistakenly selecting a wrong address (a mistake in a check).
Furthermore, there may be some people having the first family and second name in an intra-company network in the size of tens of thousands people. In this case, the addresses of these people are distinguished by adding a number and the like. However, it is difficult to instantly distinguish a plurality of similar addresses including numbers in the displayed notice. Even if a “first name” is the same (for example, suzuki or satoh), it is still possible to distinguish addresses by then “second names” as long as the “second names” are different. However, if the “second names” are similar, it is not possible to prevent a human error in a check on a displayed notice of a plurality of mail addresses.
As described above, in a case of the conventional email transmission systems, a mail address database includes all the source addresses of return mails which have been normally received heretofore, but some of the source addressed are old addresses which do not reflect a log of currently used mails. When the address database includes addresses which are not currently used at all, some of the addresses are registered as addresses which may cause mis-transmission. If a human error occurs in a check on a destination address when a destination address candidates are displayed by using this address database, the mis-transmission of an email happens. Such mis-transmission cannot be prevented only by allowing a sender to check a displayed destination address while using an address database (an address book) in which all the past records of used addresses are simply reflected, and by checking the display of a destination address.